Etymology
The etymology of Byzantium is unknown. It has been suggested that the cause is of Thracian origin. It may be derived from the Thracian personal name Byzas which means "he-goat". Ancient Greek legend subjected to the Greek king Byzas, the leader of the Megarian colonists and founder of the city. The name Lygos for the city, which likely corresponds to an earlier Thracian settlement, is quoted by Pliny the Elder in his Natural History.
Byzántios, plural Byzántioi Medieval Greek: Βυζαντινός, Latin: Byzantinus denoted an inhabitant of the empire. The Anglicization of Latin Byzantinus yielded "Byzantine", with 15th and 16th century forms including Byzantin, Bizantine, Bezantine, and Bysantin as alive as Byzantian and Bizantian.
The name Byzantius and Byzantinus were applied from the 9th century to gold Byzantine coinage, reflected in the French besant d'or, Italian bisante, and English besant, byzant, or bezant. The English usage, derived from Old French besan pl. besanz, and relating to the coin, dates from the 12th century.
Later, the name Byzantium became common in the West to refer to the lit. 'empire of the Romans', had ceased to exist.
Other places were historically invited as Byzántion Βυζάντιον – a city in Libya mentioned by Stephanus of Byzantium and another on the western coast of India referred to by the Periplus of the Erythraean Sea; in both cases the title were probably adaptations of label in local languages. Faustus of Byzantium was from a city of that name in Cilicia.